Morihei Ueshiba was a Japanese martial artist and founder of the martial art of aikido. He is often referred to as "the founder" Kaiso (開祖) or Ōsensei (大先生/翁先生), "Great Teacher".

Martial arts are codified systems and traditions of combat practiced for a number of reasons such as self-defence; military and law enforcement applications; competition; physical, mental, and spiritual development; entertainment; and the preservation of a nation's intangible cultural heritage.